Current theme

Set the current theme through the Current value, e.g. Current=archlinux-simplyblack.

Editing themes

The default SDDM theme directory is /usr/share/sddm/themes/. You can add your custom made themes to that directory under a separate subdirectory. Note that SDDM requires these subdirectory names to be the same as the theme names. Study the files installed to modify or create your own theme.

Testing (Previewing) a Theme

You can preview an SDDM theme if needed. This is especially helpful if you are not sure how the theme would look if selected or just edited a theme and want to see how it would look without logging out. You can run something like this:

$ sddm-greeter --theme /usr/share/sddm/themes/breeze

This should open a new window and show a preview of the theme.

Note: This is just a preview. In this mode, some actions like shutdown, suspend or login will have no effect.

Mouse cursor

To set the mouse cursor theme, set CursorTheme to your preferred cursor theme.

User Icon (Avatar)

SDDM reads the user icon (a.k.a. "avatar") as a PNG image from either ~/.face.icon for each user, or the common location for all users specified by FacesDir in an SDDM configuration file. The configuration setting can be placed in either /etc/sddm.conf directly, or, better, a file under /etc/sddm.conf.d/ such as /etc/sddm.conf.d/avatar.conf.

To use the FacesDir location option, place a PNG image for each user named as username.face.icon into location specified in for FacesDir in the configuration file. The default location for FacesDir is /usr/share/sddm/faces/. You can change the default FacesDir location to match your requirements. Here is an example:

/etc/sddm.conf.d/avatar.conf

[Theme]
FacesDir=/var/lib/AccountsService/icons/

The other option is to put a PNG image named .face.icon at the root of your home directory. In this case, no changes to any SDDM configuration file is required. However, you need to make sure that sddm user can read the PNG image file(s) for the user icon(s).

Note: In many KDE versions, the user icon image file is ~/.face and ~/.face.icon is a symlink to that file. If the user icon images are symlinks, you need to set proper file permissions to the target files.

Numlock

Rotate display

DPI settings

Sometimes it is useful to set up correct monitor's PPI settings on a "Display Manager" level. To do so you need to find ServerArguments parameter in sddm.conf and add -dpi your_dpi at the end of the string.

For example:

/etc/sddm.conf.d/dpi.conf

[X11]
ServerArguments=-nolisten tcp -dpi 94

Enable HiDPI

Create the following file:

/etc/sddm.conf.d/hidpi.conf

[Wayland]
EnableHiDPI=true
[X11]
EnableHiDPI=true

Troubleshooting

Long load time before SDDM shows the greeter

A low entropy pool can cause long SDDM load time. See Random number generation for suggestions to increase the entropy pool.

Hangs after login

Try removing ~/.Xauthority and logging in again without rebooting. Rebooting without logging in creates the file again and the problem will persist.

SDDM starts on tty1 instead of tty7

SDDM follows the systemd convention of starting the first graphical session on tty1. If you prefer the old convention where tty1 through tty6 are reserved for text consoles, change the default value of MinimumVT variable, which comes under the [X11] section:

/etc/sddm.conf.d/tty.conf

[X11]
MinimumVT=7

One or more users do not show up on the greeter

Warning: Users set with a lower or higher UID range should generally not be exposed to a Display manager.

SDDM only displays users with a UID in the range of 1000 to 65000 by default, if the UIDs of the desired users are below this value then you will have to modify this range. For example, for a UID of 501, say:

SDDM loads only US keyboard layout

SDDM loads the keyboard layout specified in /etc/X11/xorg.conf.d/00-keyboard.conf. You can generate this configuration file by localectl set-x11-keymap command. See Keyboard configuration in Xorg for more information.

SDDM may also incorrectly display the layout as US but will immediately change to the correct layout after you start typing your password [3]. This seems to not be a bug in SDDM but in libxcb (version 1.13-1 as of 2018) [4].

Screen resolution is too low

Issue may be caused by HiDPI usage for monitors with corrupted EDID: [5]. If you have enabled HiDPI, try to disable it.

If even the above fails, you can try setting your screen size in a Xorg conf file:

Long load time on autofs home directory

SDDM by default tries to display avatars of users by accessing ~/.face.icon file. If your home directory is an autofs, for example if you use dm-crypt, this will make it wait for 60 seconds, until autofs reports that the directory cannot be mounted.